Radio apparatus



Aug. 31 1926.

A. A. KENT RADIO APPARATUS Filed Nov. 29, 1922 2 Sheets-Sheet 1 1 ATTORNEY.

Aug. 31 1926. 1,597,901

A. A. KENT RADIO APPARATUS Filed Nov. 29, 1922 2 Sheets-Sheet .2

INVENTOR.

in M$J 4 A TTORNE Y.

MMM'

Patented Aug. 31, 1926.

PATENT OFFICE.

ARTHUR ATWA TEB KENT, OI ARDMOBE, PENNSYLVANIA.

RADIO APPARATUS.

Application ma November 2a, 1922... Serial Io. aoaaoo.

My invention relates to apparatus for reducin in circuits, and particularly recelving circuits, of systems utilizing high frequency or radio frequency currents, as in radio or analogous systems utilized for telegraphy, telephony or other purposes, the effects of undesired or parasitic currents locally produced in the apparatus, or caused or produced by static, atmospherics, strays or other natural electrical disturbances, or due to electro-radiant or other energy, particularly when such effects are due to current or currents of frequency higher than the current or currents representing the desired signal, message or control.

In accordance with my invention, when a magnetically inductive winding is utilized to convey signal or control oscillations or current to the detector or the input circuit of a thermionic device, a condenser of suitably small capacity is connected across the winding or'a suitable part thereof, whereby the parasitic or undesired currents, and particularly those of frequencies which are hi h compared with the frequency of the oscil ations or audio frequency current of the desired signal or control, are in effect short circuited or shunted from having an effect u on the detector or upon the input circuit of the thermionic device.

Further in accordance with my invention,

- the aforesaid condenser or capacity may have for one of its plates or armatures the aforesaid winding itself, or a portion thereof, another plate or armature of the capacity or condenser being a sheet of conductive material insulated from, but positioned close to, the winding.

My invention resides in the features of structure, and arrangement of connections of the character hereinafter described and claimed.

For an illustration of one of the various forms my apparatus may take, reference is to be had to the accompanying drawings, in

which:

Fig. 1 is a diagram of radio receiving apparatus embodying my invention.

Figs. 2 and 3 are side and end views respectively, of a transformer embodying my invention.

Fig. 4 is a vertical sectional view of twostage amplifying apparatus embodying my invention.

Fig. 5 is a top plan view of a portion of the structure shown in Fig. 4. v

Fig. 6 is a vertical sectional view, some arts in elevation, of a transformer unit emodying my invention.

Fig. 7 is a top plan view of the structure shown in Fig. 6 with the cover removed.

Fig. 8 is a top plan view of a cover such as indicated in Fig. 6.

Referring to Fig. l, A re resents an antenna or any other suitable absorption structure for absorbing from the natural media the electro-radiant energy representing a signal, message or other effect, or represents a conductor extending between stations and traversed by high frequency carrier waves. The path of the antenna A includes the adjustable primary P of an oscillation transformer-whose secondary is indicated at S. The primary P is connected to earth or other counter-capacity E, a variable condenser C, connected in shunt to the tuning inductance P, serving to tune the circuit or path A to the frequency of the oscillations representing the deslred signal, message or other effect. The condenser C is connected in arallel relation, as indicated, for relatively long waves, it being well understood in the art thatsuch condenser .may be serially connected in the antenna path for tuning the same to short waves.

shunting the secondary S is the variable condenser G for tuning the circuit S, C to the frequenc of the oscillations representing the desired .ignal, message or other efi'ect. V is an audion orsimilar thermionic vacuum tube comprising the anode a, grid g, and filament or cathode f, the latter traversed by current fromthe battery 8 and controllable in magnitude by the rheostat 1'.

As well understood in the art, the grid 9 and cathode f may be connected, respectively, to opposite terminals of the condenser C. There may intervene in the circuit of the grid 9 the condenser C shunted by the high resistance R. In the anode circuit of the tube V is the source of current or battery B and the primary P of a preferably audio 584d a y and the primary P of a sec- 1 0nd preferably audio frequency transformer, the terminals of whose secondary S are connected, respectively, to the grid 9 and cathode of a further thermionic vacuum tube amp ifier V in the circuit of Whose anode a is connected the aforesaid batter B and any suitable translating device which maybe the winding or windings of a telephone receiver, or of any other signal-translating device, or may be the primary of a further transformer controlling directly 9. translating device, as a telephone receiver, or controlling the input circuit of a further amplifying vacuum tube.

The apparatus as thus far described is per se not my invention, and is well understood in the art of radio reception. v

In accordance with my invention, however, I connect across the grid 9 and the cathode f of each of the vacuum tubes V and V or across the terminals of the transformer secondaries S and S, a condenser of relatively small capacity, whereby there are short circuited, or shunted from the grids of the tubes V V all transient or continuous undulator or oscillating currents of frequency relatively high as compared with the audio frequency of the undulations representing the desired signal, message or control, whereby the effects upon the ultimate translating device, as a signaltranslating device or telephone T, of the higher harmonics of the oscillations representing the desired signal or message, the higher harmonics of other oscillations corresponding with or caused by absorbed electro-radiant energy, the relatively high frequency currents caused by atmospherics, static, strays, and the relatively high frequency currents corresponding with the frying, sizzling or other noises due to the interactions between the circuits of a thermionic tube or the reactions upon each other of the circuits of several thermionic tubes, are greatl reduced, and to such extent reduced that t e desired signals or messages or controls may be heard or effected wtihout accompaniment by parasitic noises due to the causes aforesaid, or other causes.

In the example illustrated in Fig. 1, one armature or plate of the by-passing or shunting condenser or capacity is the winding, or a portion of the winding, of the 0011 S or S itself, and the other plate or armature of the condenser or capacity is the sheet, late, ribbon or other suitable structure of conducting material, as tin or other metallic foil, or equivalent, insulated from but placed suitably closely adjacent-the winding 8*.

As indicated in Fig. 1a, however, the .bypassing or shunting capacity or condenser may be be of the usual type comprising two plates or armatures, as in usual or ordinary condensers, as indicated at C, And in Fig.

paper or other insulating tu 1b is indicated a crystal detector D shunted by the condenser C, operating similarly, as in Figs. 1 and 1a.

By way of example, it may be stated that the capacity of the condenser whose armature is K, Fig. 1, may be of the order of from about .0002 microfarad to about .001 microfarad, which is a capacit many times smaller than the capacity wh1ch would be necessary to tune or approximately tune a circuit utilized for the frequency of the By way of example, it may be stated that v each of the rimaries P, P ma comprise 6000 turns oi No. 38 Brown & S arp gauge copper wire, disposed in fourteen layers, and the winding having an internal diameter of approximately one inch, and the windin having, for irect current, a resistance 0 about 1125 ohms. The secondary S for such a primary is disposed within the rimary, and may comprise 17,000 turns of the aforesaid No. 38 wire, disposed in forty layers, and having a direct current resistance of about 2000 ohms, the external diameter of the winding being approximately {#22 of an inch diameter, and having an internal diameter of about f}; of an inch, the primary being wound upon a paper tube whose internal diameter is about 3 of an inch and the secondary wound upon a paper tube whose internal diameter is about of an inch, filled with iron wire of the character hereinafter referred to.

Referring'to Figs. 2, 3, 4 and 5, the iron wire core of the aforesaid transformer is indicated at I, and consists of a bundle of wires whose length is great compared with the length of the windings, the bundle divided into parts, as halves, and bent across the ends and extending longitudinall of the windings, as indicated at I, theen of the wires coming close to each other or overlapping each other, as indicated in Figs. 2 and 5, the magnetic circuit accordingly being substantially closed or of the hedgehog type. The core I is dis osed within the 6, upon which is wound the secondary S or S, disposed withinthe aper or-other tube 0, upon which is wound the outer or surrounding primary dered or otherwise connected to the strip rial, as tin foil, or very thin sheet copper or other suitable material. For a transformer of the dimensions given in the foregoing exam le, the sheet K may be rectangular an of the order of one and oneei hth inches long and one inch wide, and when of tin foil may have a thickness of the order of .0003 inch, whereby it occupies extremely small space. There is then placed upon this condenser armature or plate K a tin, copper or other metallic ribbon d extending longitudinally of the secondary winding from the plate K, which may be placed adjacent one end. of the secondar winding, to the opposite end of the win To bind the plate K and the conducting stri d in contact therewith, and both in fixe sition on the outside of the secondary winding, they are overlaid with a binder strip of mmed pa er or other suitable material. fter assem l of thesecondary coil and the plate K within the tube a in operative relation to the outer rimary winding, the strip (1 is bent outwar ly across the end of the tube 0 and the insulating sheets of the rimary winding to position, as indicated in i'gs. 2, 3 and 5, and the conducting w1re or lead e connecting to the terminal of the inner layer of the secondary winding is $05- as indicated at h, Fig. 3. A wire or ead i is connected to the terminal of the outer posed near a layer of the secondary windingand is electrically connected with the remote terminal of such winding, this being feasible or practicable because between that layer of the secondax winding which acts as the condenser plate or armature complemental to the armature or plate K and the terminal of the remote layer there are many turns, offering both high inductance and considerable resistance, which prevents short circuiting the condenser, though there is in effect connected across its armatures a high inductance, or a resistance, or a high impedance.

A indicated'in Figs. 4 and 5, the transformers with their condenser armatures or plates K may be disposed within a sheet iron or steel or other metallic casing F, having the wall or cover G of insulating material, for exam 1e, molded condensite or ba-kelite or the li e, upon whichare disposed the sockets H, adapted to receive and hold vacuum tube devices, as V, V, or V, V, the usual contacts, adjustable resistance for filament, etc., being carried by the coverG, as well as the usual binding posts for suitably connecting the apparatus in circuit. By preference, the transformers may be reyersely positioned, as indicated in Fig. 5;

that is, with symmetrically or similarly constructed transformers they are disposed within the casing with their similar parts lying in opposite directions. The transformer units may be held in the casing F in any suitable way. As indicated,,h,owever, they are embedded in congealed bituminous, asphaltic or other insulating or binding material J.

Referring to Figs. 6, 7 and 8, there is' shown a transformer unit per se housed within a metallic, fibrous, paper or other casing M, having the base 0. Extending across the top of the transformer unit and f'rictionally engaging the inside walls of the casing M is the wooden or other member 72, forced down upon or holding the transformer unit in place. After the application of the member there may be flowed into the container over the top of the transformer unit and around the member 2' the bituminous, asphaltic or other insulating or binding material J, which solidifies and binds and insulates the parts. Surmountin the casing M is the cap cover N, preferably ofinsulating material, as molded condensite, bakelite or the like, carrying binding posts g, t, 'u. and 'v, of which 9 and t are the primary binding posts to which are connected the aforesaid primary leads k and m, extending upwardly through the cover N and attached to the binding posts. Similarly, to the posts u and oare connected the aforesaid secondary and condenser leads 6 and i, extending through the cover N and attached to the binding posts. These leads may be connected to the binding posts, and the cover then placed and secured in position after introduction of the material J into the casing M.

As indicated in Fig. 7, the core wires extending across the end and alon the outside of the unit are more Widely istributed over the surface of the unit than in the case of Figs. 3 and 4.

By the utilization of the condenser structure whose armature is K in connection with a winding, the parasitic noises, such as hisses, sizzling, frying, crackling and the like are greatly reduced and in some instances eliminated, makin reception of radio telephonic messages, an telegraphic or other signals, more agreeable, an rendering the signals or messages more clearly ble or distinguishable.

Particularly in radio receiving appartus utilizing vacuum tubes as indicated in Fig. 1, there occur within the receiving apparatus and readily intelligiitself, and independently of received signal energy or static effects, undulatory or transient current effects of high frequency causing frying, crackling and similar noises which interfere with the desired signals or messages. But by the use of a condenser of small capacity in the relations herein described, these undesired eifects are greatly reduced or eliminated.

In general, the magnitude of the capacity of the condenser whose armature or plate is K, is smaller than the capacity of a condenser which would attune the circuit to the frequency of the received energy or to the frequency of the oscillations representing the desired signal or message. More particularly, the magnitude of the capacity in accordance with my invention is a fraction, and preferably a small fraction of the capacity of the condenser which would be utilized for tuning the circuit to the he uency of the oscillations representing the desired signal or message.

By employment of a condenser of small capacity as described, there is offered by the condenser easy passage for decadent or sustained current Waves or oscillations of a frequency materially higher than the frequency of the oscillations representing the desired signal or message, or, in general, easy passage for current, whether undulatory or aperiodic, having a materially steeper wave front than the oscillations representing the desired signal or message. And on the other hand, the capacity of'the condenser is so small that the condenser offers relatively high opposition to passage therethrough of currents of the frequency of the oscillations or audio frequency current representing the desired signal or message. In consequence, the oscillations or current'representing the desired signal or message are not to any substantial or serious degree bypassed through the condenser, but are caused to afiect to desired and usual degree the potential of the grid 9 of a vacuum tube, as in Fig. 1, or the detector D, as in Fig. 1

lVhat I claim is:

1. The combination with a winding having a plurality of layers, of a condenser armature disposed in capacitative relation to one of said layers and forming therewith a condenser, and a connection from said armature to a remote terminal of another of said layers.

2. The combination with a winding having a plurality of layers, of a condenser armature connected to one layer of said winding and disposed in capacitative relation to another layer of said winding remote from said connection and forming with said portion of said winding a condenser.

3. The combination with a winding having a plurality of layers, of a condenser armature comp ising a thin sheet of conductingmateria disposed in close relation to and insulated from the outer layer of said winding and forming with said winding a condenser.

4. The combination with a winding having a plurality of layers, of a condenser armature comprising a thin sheet of conducting materia connected to an inner layer of said windin and disposed in close relation to and insu ated from the outer layer of said winding and forming therewith a condenser.

5. The combination with a windin for coupling thermionic devices, of a con enser armature connected to a said winding and disposed in capacitative relation to a portion of said winding remote from said connection and forming therewth a condenser.

6. The combination with a transformer for coupling thermionic devices, of a condenser armature connected to the secondary winding of said transformer and dis sed in capacitative relation to a portion 0 said winding remote from said connection and forming therewith a condenser.

7. The combination with an audio frequency transformer for coupling thermionic devices, of a condenser bridging the terminals of a windin of said transformer, said condenser having as armatures said winding and a condenser armature disposed in capacitative relation thereto.

8. The combination with an audio frequency transformer for con ling thermionic devices, of a condenser bri ging the terminals of the secondary winding of said transformer, said condenser having as armatures said winding and a condenser armature dis-' posed in capacitative relation thereto.

9. The combination with an audio fre- Y quency transformer for coupling thermionic devices, of a condenser armature consisting of a thin sheet of conducting material disposed closely adjacent to and insulated from a winding of said transformer and forming with said winding a condenser.

10. The combination with an audio frequency transformer for coupling thermionic devices, of a condenser armature connected to a winding of said transformer and disposed in capacitative relation with a portion of said winding remote from said connection.

11. The combination with an audio frequency transformer for coupling thermionic devices, of a condenser armature connected to the secondary winding of said trans former and disposed in capacitative relation with a portion of said winding remote from said connection.

12. A transformer for coupling thermionic devices, comprising primary and secondary windings, one of said windings disposed. within the other, and. a c ndenser armature disposed between said windings and in capacitative relation to one of said windings and forming therewith a condenser.

13. A transformer for coupling thermionic devices, comprising primary and secondary windings, the secondary winding disposed within the primary winding, a condenser armature positioned between the secondary and primary windings and disposed in capacitative relation to said secondary winding and forming therewith a condenser.

14. The combination with a winding comprising a plurality of layers, of a condenser armature consisting of a sheet of conducting material disposed in close relation to a layer of said winding and connected to a remote layer of said winding.

15. The combination with a winding, of a condenser armature disposed in capacitative relation to said winding and forming therewith a condenser, and a high impedance connection between said armature and said winding.

16. The combination with a coil of a .second coil surrounding said coil, and a condenser armature disposed between said coils and forming with at least one of them a condenser.

17. The combination with a transformer for coupling thermionic devices, a winding of said transformer having a plurality of layers, of a condenser armature-disposed in capacitative relation to one of said layers and forming therewith a condenser, and a connection from said armature to a remote terminal of another of the layers of said winding.

18. The combination with a transformer for coupling thermionic. devices, a winding of said transformer having a plurality of layers, of a condenser armature disposed in capacitative relation to one of said layers and forming therewith a condenser, and a connection from said armature to a remote terminal of another of the layers of said winding, said transformer having a second Winding between which and said first named winding said condenser armature is disposed.

19. The combination with a winding, of a condenser armature disposed in capacitative relation with a portion only of said winding adjacent one terminal thereof and forming therewith a condenser, and a connection from said armature to the remote terminal of said winding, whereby there exists high impedance between said remote terminal of said Winding and that portion thereof coacting with said armature to form a condenser.

In, testimony whereof I have hereunto affixed my signature this 27th day of November, 1922.

ARTHUR ATWATER KENT.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,597,901, granted August 31,

1926, upo for an improvement in tion requiring correction as wtihout read without,-. same page,

n the application of Arthur Atwater Kent, of Ardmore, Pennsylv an1a,

Radio Apparatus, errors appear 1n the pr nted specificafollows: Page 2, line 47, for the misspelled word line 61 strike out the paragraph beginning with the word As and all to and through the words in Figs. 1 and 1", in line P 97, after the word cap insert read currents, and line 84, for

3, line 37, for the word of, second occurrence, read or; same the word or; page 4, line 31, for the word current therewth read therewith; and that the said page, line Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the PatentOlfice;

Signed and sealed this 26th day of October, A. D. 1926.

A. KINNAN, Acting Omn/mz'ssiQner of Patents. 

